With the advent of the enclosed pickup truck bed, numerous apparatus and methods have been sought and suggested on how best to cover such a box in order to protect its contents. Further, with the modern trend toward a more extensive use of light utility vehicles, a concomitant need has arisen to afford versatile coverings that could also afford protection from the elements to human or animal occupants during a traveler's periods of rest or encampment. Some of the solutions are very practical and cover the spectrum from canvas tonneau covers to pickup bed-insertable camping or light housekeeping units. All of these apparatus, however, have or share at least one of several disadvantages. As the following discussion of the prior art dealing with pickup truck box covers will show, the most serious common disadvantage is the fixing of any cover by means that violate the integrity of the pickup box, i.e., place holes in the body of the vehicle. Another serious drawback to modern covers is that of excessive weight. Even the canvas type tonneau cover, when rolled and prepared for removal, weighs a considerable amount. As one familiar with the art may readily see, attachment of a canvas cover requires, in many cases, as many as 50 perforations of side-wall and tailgate ridges. A third, and often weighty disadvantage is that, in all of the prior art that the inventor was able to obtain through diligent searching of the patent files and literature, the removal of all covers leaves the owner either superfluous hardware or violations of the pickup body integrity with which he or she must contend. In northern climates, where salt is often used to remove ice and snow from the rods, such superfluous hardware or perforations in the body rapidly become points of corrosion. Two pertinent patents, U.S. Pat. Nos. 4,199,188 and 4,406,493 were issued to Albrecht in 1980 and 1983, respectively. The concept which is common to both of these inventions is the use of sectional, or modular, pickup bed covers that are emplaced transversely and sequentially on the pickup box, employing a set of side rails. The rails of both inventions are affixed to the sidewall upper margins (ridges) by screws or bolts. These inventions disclose an adjunct locking means which secures the tailgate against a portion of a modular unit (the rearmost unit) by locking the tailgate, with an ordinary clasp, to the rear margin of one or both of the sidewalls. The attachment of such a locking mechanism further violates the integrity of the box.
In a U.S. Pat. No. 4,615,557 issued to Robinson in 1986, there is disclosed a security cover for placement on the bed of a truck that includes a mounting frame on the top of the upper margins of the side walls, as well as transverse frame members for each of the two sections of the cover. As in U.S. Pat. Nos. 4,406,493 and 4,199,188, this invention bolts a frame to the sidewalls.
The patent issued to Anderson, No. 3,640,865, in 1972 hardly qualifies as a sectionalized or modular assembly in that the sections of this invention are telescoping sections which ride on a continuous railing. Thus, the entire unit is composed of a rather heavy assembly; and the rail portions are bolted to the sidewalls. An interesting aspect of this invention is that the rear telescopic section bears a hinged panel member that, when closed and secured, overlaps a closed tailgate. Anderson thus achieves his primary objective, that of mounting a cover that will adequately secure the pickup box contents.